Population TheoriesTheories of Demographic Transition

Demographic Transition is the phenomenon of a country’s death and birth rates changing over time from high to low.

Over time, the average family size has decreased in every country of the world.

In approximately 60 countries, the total fertility rate has fallen to less than 2.1. Canada is one of these countries.

Stage 1: Pre-transitionStable populationHigh birth rate and

death rateFertility rate of 8 or

moreExtremely high infant

mortality rateMany young children,

very few older peopleNo country in the

world is still at the pre-transition stage.

Stage 2: Early TransitionVery rapid increase in

populationDeath rate declines

rapidlyFertility rate remains

highInfant mortality rate

declinesHigh birth rateMany young peopleEarly Transition is

marked by death control

Stage 3: Late TransitionPopulation growth

slows downBirth rate declines

rapidlyDeath rate declines

slowlyFertility rate

declinesIncreasing number

of older peopleLate Transition is

marked by birth control

Stage 4: Post-transitionStable or slow

population increaseLow birth rate and

death rateFertility rate less

than 2.1Many older people

which leads to a high dependency load

Stage 5:? (doesn’t fit the model, but is happening now!)Declining populationExtremely low birth

rateDeath rate is lowFertility rate less

than 2A lot of older people

Is it permanent or just a temporary trend???

Differing Ideas About Population GrowthOptimistic vs. Pessimistic

Optimistic ViewsHistorically, large families and

a growing population have been desirable for various reasons.

1. Religious Reasons: More Children = More Followers and More Followers = More Political/Social Power

2. Non-Religious Reasons: Leaders needed larger numbers to support their economic and military expansionist desires.

CornucopiansCornucopians believe that humans have the

ability to find technological innovations that will increase the earth’s carrying capacity.

The Agricultural and Industrial Revolutions would be their evidence.

A cornucopian may say that the next major human innovation will solve our energy crisis without damaging the environment.

Bogue (1960’s)D.J Bogue’s theory of demographic

regulation stated that over an extended period of time, a society will naturally limit its own population in accordance to the Earth’s ability to support it.

Bogue’s theory is supported by the demographic transition model and in the fact that some countries have tried to limit their population growth in recent years.

Pessimistic ViewsCritics have all made

the same basic point – Earth is of finite size and has an ability to support only a certain level of population.

Thomas Malthus William CattonWarned of population

problems in his writing in 1798.

Pop. grows in a geometric sequence (1,2,4,8,16. . .) while food grows arithmetically (1,2,3,4 . . .)

Only result is onset of “misery”. (famine, disease, war)

Expanded on Malthus’ views in 1980’s.

Introduced idea of Earth’s carrying capacity; it can only be exceeded at the expense of the environment.

Suggests we’re beyond the carrying capacity now only because we’re using up the world’s fixed stock of natural resources for future generations.